 {% macro render_dialog(title, class='dialog') -%}
  <div class="{{ class }}">
      <h2>{{ title }}</h2>
      <div class="contents">
          {{ caller() }}
      </div>
  </div>
 {%- endmacro %}
 
 {% call render_dialog('Hello World') %}
     This is a simple dialog rendered by using a macro and
     a call block.
 {% endcall %}
